Exploring the Analytical Potential of NMR Spectroscopy in Chiral Anisotropic Media for the Study of the Natural Abundance Deuterium Distribution in Organic Molecules - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Analytical Chemistry Année : 2004

Exploring the Analytical Potential of NMR Spectroscopy in Chiral Anisotropic Media for the Study of the Natural Abundance Deuterium Distribution in Organic Molecules

Résumé

The deuterium/hydrogen (D/H)i ratio measurement by quantitative 2H NMR spectroscopy is a method of choice for the analysis of kinetic isotopic effects associated with enzyme-catalyzed reactions during a biosynthetic pathway. However, the efficiency of the current isotropic 2H-{1H} NMR can be limited by the rather small chemical shift dispersion of deuterium nuclei. In addition, this method does not allow the enantiotopic deuterons in prochiral molecules to be spectrally discriminated, hence preclud-ing the quantification of isotopic fractionation on methyl-ene prostereogenic sites. In this work, we explore another analytical strategy able to circumvent these disadvantages. This approach is based on the use of natural abundance 2H 2D NMR experiments on solutes embedded in polypep-tidic, chiral liquid crystalline solvent. Thus, we show that NMR in these oriented phases is a powerful way to separate deuterium signals on the basis of the quadru-polar interactions, providing a promising alternative to overcrowded 2H NMR spectra obtained in liquid state. To illustrate our purpose, we have experimentally investigated the case of 1,1′-bis(phenylthio)hexane derived by cleavage from methyl linoleate of safflower. The 2H NMR results in chiral liquid crystals are presented and dis-cussed. We show, for the first time, that (D/H)pro-R and (D/H)pro-S can be measured at the same methylene position of a fatty acid chain.

Dates et versions

hal-03008466 , version 1 (16-11-2020)

Identifiants

Citer

Philippe Lesot, Christie Aroulanda, Isabelle Billault. Exploring the Analytical Potential of NMR Spectroscopy in Chiral Anisotropic Media for the Study of the Natural Abundance Deuterium Distribution in Organic Molecules. Analytical Chemistry, 2004, 76 (10), pp.2827-2835. ⟨10.1021/ac030385e⟩. ⟨hal-03008466⟩
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